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The composition of the catalyst layer plays an important role in the carbon dioxide reduction reaction (CO 2 RR), since it influences greatly the mass diffusion rate and the accessibility of active sites. Until now, tremendous efforts have been dedicated to the development of cathode materials with innovative characteristics, while scarce efforts have been concentrated on the study of the catalyst layer aiming at maximizing the performance of the electrodes toward the CO 2 RR. This work focuses on a full investigation of the key electrode components and their effects on the CO 2 RR performance. It is found that all key components such as Nafion binder, zinc oxide catalyst and carbon black conductor significantly affect the current density and the faradaic efficiency for carbon monoxide (CO) formation. [Display omitted] • A thorough study of the composition of a ZnO-based electrode is conducted for CO 2 RR. • All key components show significant effects on CO selectivity and production rate. • Nafion favors charge transfer while it limits electron transport and CO 2 diffusion. • Carbon black considerably increases electrical conductivity. • ZnO loading is associated with the number of active sites and their accessibility. [ABSTRACT FROM AUTHOR]

Many research efforts point nowadays towards the development of flexible, lightweight and efficient energy storage devices. Herein we report a simple procedure for the fabrication of nanostructured electrodes based on Cu x O nanowire/nanoporous layer grown on copper foils and we propose, for the first time to the best of our knowledge, their integration into solid-state pseudo-supercapacitors. An easy and scalable thermal oxidation process in ambient atmosphere is employed to grow a Cu x O film on Cu substrates. Electron microscopy, contact angle measurements, infrared and X-Ray photoelectron spectroscopy are employed to obtain a deep understanding of the morphology, wettability, structure and composition of the copper oxides. We show that the annealing time strongly influences the nanostructures formation promoting the evolution of the oxide film from Cu 2 O to CuO/Cu 2 O bilayer with the subsequent growth of CuO nanowires. The obtained materials represent flexible and binder-free electrodes for pseudo-supercapacitors in which the current collector and the active element are joined in the same substrate without further processing. The electrical characterizations of symmetric devices fabricated with a polymeric electrolyte show the pseudo-capacitive behavior of the proposed nanostructures. [ABSTRACT FROM AUTHOR]

Developments are reported in the catalytic synthesis of biaryls containing an ortho -carbaldehyde or 6 H -dibenzopyrans in the presence of palladium/norbornene as catalyst. The reaction of o -substituted aryl iodides and o -bromobenzyl alcohols proceeds by unsymmetrical aryl-aryl coupling to form a seven-membered oxapalladacycle intermediate, which may undergo an intramolecular redox process to form carbonyl groups or a C–O coupling to six-membered cyclic ethers. The predominant formation of dibenzopyrans as well as of biaryl structures containing the oxidized CHO group in one ring and the reduced CH 2 OH in the other is described along with some mechanistic insights. [ABSTRACT FROM AUTHOR]

Abstract: Objective: The aim of this study was to evaluate, through the Scanning Electron Microscopy, the loop closure of four types of stapedial prostheses and to compare the different systems of crimping to the long process of the incus. Materials and methods: Four types of stapedial prostheses (one platinum-teflon, two different titanium and one nitinol-teflon pistons) were inserted in 40 specially prepared temporal bones simulating the in vivo stapedotomy procedure. Two pistons were crimped by single manual manoeuvre with a McGee microforceps; the remainders were self-retained and thermal-crimped, respectively. All the specimens were evaluated through the Operative Microscopy and the Scanning Electron Microscopy. Results: Through the Operative Microscopy, all prostheses apparently achieved a correct adhesion to the long process of the incus; on the contrary the Scanning Electron Microscopy study demonstrated some limits of the manual crimping and the different coupling with the ossicular chain of each type of stapedial prosthesis. Conclusion: A complete adhesion of the prosthetic loop cannot be obtained because of the irregular profile of the incus at the site of attachment of the stapedial prosthesis. Consequently, on the basis of the morphological analysis with Scanning Electron Microscopy, in the surgical practice, the preference could be given to the stapedial prostheses that achieve greater contact such as the self-retaining and thermal crimping pistons compared to the standard sized prostheses considered. [Copyright &y& Elsevier]

This work aims to improve upon the aluminium impact attenuator currently used by the University of Lisbon Formula Student team through a composite solution. The influence of geometrical variations, particularly the use of curved walls, and the number of objectives considered for the optimization are studied. To perform the optimizations, Abaqus is coupled with the Direct Multisearch (DMS) algorithm, the overall performance of the solutions is evaluated and the influence of the introduction of curved walls on the energy absorption capabilities discussed. Off-axis impacts are studied and the effect of curved walls in that situation analysed. An overview of the best configurations achieved is provided and one final configuration is selected. • Design and optimization of a composite impact absorber to be used in an Formula Student car is presented. • The importance of the use of curved-walled structure was evident throughout the present work. • Off-axis impacts are studied. • To perform the optimizations, Abaqus is coupled with the Direct Multisearch (DMS) algorithm. [ABSTRACT FROM AUTHOR]

Abstract The growing interest in developing wearable energy storage devices requires the identification of suitable materials for the fabrication of their components. In this paper we report a new asymmetric fiber-shaped supercapacitor exploiting a composite of hematite and reduced graphene oxide aerogel obtained by a hydrothermal synthesis in presence of green extract as anode material and electrodeposited nanostructured MnO x as cathode. The three dimensional arrangement of the graphene flakes during the hydrothermal self-assembly process provides a highly conductive porous matrix with high surface area and, most importantly, a pores structure able to guarantee the rapid diffusion of the electrolyte ions and a fast electron transport. By simply modifying the hydrothermal recipe adding a dispersion of hematite nanoparticles, obtained using olive leaves extract as green surfactant, it is possible to obtain the decoration of the graphene network with the pseudocapacitive material. The resulting nanocomposite rGO/Fe 2 O 3 aerogel exhibits excellent pseudocapacitive behaviour and it is used, in combination with MnO x nanostructured electrode, to fabricate a flexible fiber-shaped device exhibiting superior rate capability and bending stability. The use of a green surfactant during the synthesis opens up new avenues for the fabrication of environmentally friendly electrodes for wearable energy storage applications. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

[Display omitted] • The submitted work is of great interest for the Journal Applied Energy due to its peculiar theme, the electrochemical CO 2 reduction, and for its approach in the investigation. Indeed, a complete ab initio modelling guided the experimental synthesis and testing of a molecular electrocatalyst which shows great performances for the CO2RR. • This work elucidate the possibility to activate the CO 2 through organic molecules and, moreover, shows the feasibility of this approach to be completely integrated inside a TRL 3–4 electrolysis cell. The electrochemical reduction of CO 2 to value-added products is hindered by its thermodynamic stability and by the large energy required to chemically activate the molecule. With this respect, forcing CO 2 in a non-linear geometry would induce an internal electron charge rearrangement which would facilitate further electrochemical transformations. In this work, we achieved this goal through the design of a dual function electro-organocatalyst, which exploits the ability of the imidazolate (Im-) lone pair to bind CO 2 via nucleophilic attack and then electrochemically reduce it. To give structural stability to the Im- based catalyst, the imidazoles species are incorporated into a solid structure, namely ZIF-8. Once activated by the organic Im- ligand, CO 2 is electrochemically reduced to CO when a bias is applied to ZIF-8. The catalyst proposed in our study was first devised by computer aided design based on Density functional Theory simulations and then realized in laboratory. Our results demonstrate that ZIF-8 supported on conductive CNTs presents surface Im- active sites which convert CO 2 into CO with a high faradaic efficiency (70.4 %) at −1.2 V vs reversible hydrogen electrode, by combining chemical activation with electrochemical catalysis. [ABSTRACT FROM AUTHOR]

Airborne Wind Energy Converters (AWECs) are promising devices that, thanks to tethered airborne systems, are able to harvest energy of winds blowing at an altitude which is not reachable by traditional wind turbines. This paper is meant to provide an analysis and a preliminary evaluation of an AWEC installed on a floating offshore platform. A minimum complexity dynamic model is developed including a moored heaving platform coupled with the dynamics of an AWEC in steady crosswind flight. A numerical case study is presented through the analysis of different geometrical sizes for the platform and for the airborne components. The results show that offshore AWECs are theoretically viable and they may also be more efficient than grounded devices by taking advantage of a small amount of additionally harvested power from ocean waves. [ABSTRACT FROM AUTHOR]

• CO oxidation was studied by in situ Raman spectroscopy on nanostructured ceria-based materials. • In situ Raman analyses during CO oxidation allowed to monitor defect sites in operando conditions. • Cycles of reduction (CO in N 2) and oxidation (pure O 2) at 400 °C allow to study the stability of defects. • Oxygen vacancies evolved from clusters to isolated ones according to the atmosphere and temperature. • The involvement of the defect sites in structural rearrangement is fostered by easily reducible dopants. Among the factors affecting ceria activity, the defectiveness plays a key role in the case of CO oxidation. In this study, its connection with the catalytic performance was investigated via in-situ Raman spectroscopy on nanostructured pure and Cu/Mn-doped ceria, monitoring the defect sites and surface species evolution during the reaction. The accumulation of polyene-like chains, formed through CO dissociative adsorption at the catalyst surface, was observed and their disappearance was related to the catalyst light-off temperature. Moreover, the doped samples exhibited a rise of the Raman bands associated to defects after the tests, consequence of the structural rearrangements occurring during CO oxidation. Indeed, in-situ Raman measurements during reduction (CO/N 2) and oxidation cycles at 400 °C evidenced the formation of oxygen vacancy clusters in reducing atmosphere, which could reorganize not only in O 2 but also upon a temperature decrease, forming isolated vacancies and then evolving in Frenkel and extrinsic oxidized dopant-containing sites when exposed to oxygen. [ABSTRACT FROM AUTHOR]

This paper introduces a theoretical and experimental study of a wave energy converter (WEC) that combines the two innovative concepts of U-oscillating water column (U-OWC) and dielectric elastomer generator (DEG) power take-off (PTO). The U-OWC is a type of oscillating water column that features a U-shaped duct that is introduced to tune its dynamics to a certain wave period without active means of phase-control. The DEG is a compliant polymeric generator that makes it possible to convert mechanical energy into electrical energy by exploiting the large deformations of elastomeric membranes. A lumped-parameter mathematical model of the proposed WEC has been set-up and a small-scale model/prototype has been preliminary tested in a benign real-sea environment. During experiments, relevant experimental data have been collected and used for assessing the reliability of the modelling approach. Beside the model validation, specific experiments have been conducted to test a simple but yet effective load shedding system based on the progressive opening of an air valve. Finally, a preliminary design of a full-scale U-OWC equipped with DEG-PTO has been studied through wave-to-wire analysis. The obtained numerical results show an overall performance that is comparable with that of more conventional, expensive and complex PTO technologies. • Model of a U-shaped oscillating water column with dielectric elastomer generator. • Tests on a scaled prototype are carried out in a benign sea basin. • Good agreement of model prediction and experimental data over a wide set of tests. • The model is used to predict the performance of a full-scale U-OWC with DEG. • First step toward the demonstration of the feasibility of dielectric elastomer WEC. [ABSTRACT FROM AUTHOR]

Highly efficient, separable, and stable magnetic iron-based-photocatalysts produced from ultra-stable Y (USY) zeolite were applied, for the first time, to the photo-Fenton removal of phenol under solar light. USY Zeolite with a Si/Al molar ratio of 385 was impregnated under vacuum with an aqueous solution of Fe2+ ions and thermally treated (500–750 °C) in a reducing atmosphere. Three catalysts, Fe-USY500°C-2h, Fe-USY600°C-2h and Fe-USY750°C-2h, containing different amounts of reduced iron species entrapped in the zeolitic matrix, were obtained. The catalysts were thoroughly characterized by absorption spectrometry, X-ray powder diffraction with synchrotron source, followed by Rietveld analysis, X-ray photoelectron spectroscopy, N 2 adsorption/desorption at −196 °C, high-resolution transmission electron microscopy and magnetic measurements at room temperature. The catalytic activity was evaluated in a recirculating batch photoreactor irradiated by solar light with online analysis of evolved CO 2. Photo-Fenton results showed that the catalyst obtained by thermal treatment at 500 °C for 2 h under a reducing atmosphere (FeUSY-500°C-2h) was able to completely mineralize phenol in 120 min of irradiation time at pH = 4 owing to the presence of a higher content of entrapped nano-sized magnetite particles. The latter promotes the generation of hydroxyl radicals in a more efficient way than the Fe-USY catalysts prepared at 600 and 750 °C because of the higher Fe 3 O 4 content in ultra-stable Y zeolite treated at 500 °C. The FeUSY-500°C-2h catalyst was recovered from the treated water through magnetic separation and reused five times without any significant worsening of phenol mineralization performances. The characterization of the FeUSY-500°C-2h after the photo-Fenton process demonstrated that it was perfectly stable during the reaction. The optimized catalyst was also effective in the mineralization of phenol in tap water. Finally, a possible photo-Fenton mechanism for phenol mineralization was assessed based on experimental tests carried out in the presence of scavenger molecules, demonstrating that hydroxyl radicals play a major role. [Display omitted] • Stable catalysts were prepared by entrapping Fe species in ultra-stable Y zeolite. • The catalyst's magnetic properties allow easy separation and reuse. • Complete phenol removal is achieved by solar light-driven photo-Fenton reaction. • Phenol mineralization increases with Fe 3 O 4 content in ultra-stable Y zeolite. • Hydroxyl radicals play the main role in the removal of phenol under solar light. [ABSTRACT FROM AUTHOR]

Self-standing and flexible membranes based on reduced graphene oxide (rGO)/SnO 2 nanocomposite and cellulose fibers are here presented. The flexible membranes are prepared through an easy and eco-friendly protocol: the rGO/SnO 2 nanocomposite is synthetized via a microwave-assisted procedure and then assembled with microfibrillated cellulose (MFC) through a water-based process. This process leads to the formation of a nanocomposite in which cellulose nanofibers are integrated with the graphene matrix. Beyond the good flexibility, the nanocomposite membranes present interesting properties in terms of capacitive behavior and catalytic activity: the electrochemical characterizations revealed that such material is an extremely competitive candidate for the oxygen reduction reaction, even comparable to the commonly used Pt-based catalysts. Furthermore, the possible application as electrodes for flexible supercapacitors and piezoresistive sensors is also investigated showing the great potential of such composite material. Image 1 [ABSTRACT FROM AUTHOR]

Wearable wire-shaped supercapacitors were fabricated exploiting an innovative graphene aerogel self-assembly procedure on copper wire. The innovative aspect of the proposed procedure lies in the employment, for the first time to the best of our knowledge, of a hydrothermal graphene synthesis for an in situ coverage of a non-planar substrate. Specific capacitance per unit length was calculated to be about 12,5 mF/cm. The device can sustain repeated charge–discharge and bending cycles without suffering significant deterioration of specific capacitance. The combination of graphene aerogel self-coating method, flexibility and superior electrochemical performance makes the proposed device a suitable power source for e-textile applications. [ABSTRACT FROM AUTHOR]

Among novel technologies for producing electricity from renewable resources, a new class of wind energy converters has been conceived under the name of Airborne Wind Energy Systems (AWESs). This new generation of systems employs flying tethered wings or aircraft in order to reach winds blowing at atmosphere layers that are inaccessible by traditional wind turbines. Research on AWESs started in the mid seventies, with a rapid acceleration in the last decade. A number of systems based on radically different concepts have been analyzed and tested. Several prototypes have been developed all over the world and the results from early experiments are becoming available. This paper provides a review of the different technologies that have been conceived to harvest the energy of high-altitude winds, specifically including prototypes developed by universities and companies. A classification of such systems is proposed on the basis of their general layout and architecture. The focus is set on the hardware architecture of systems that have been demonstrated and tested in real scenarios. Promising solutions that are likely to be implemented in the close future are also considered. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis of a series of azobenzene containing liquid crystalline methacrylic homopolymers, poly(4-ω-methacryloyloxy-hexyloxy-4′-ethoxyazobenzene) [Poly(M6A)], with distinct average chain lengths and low polydispersity has been achieved by Atom Transfer Radical Polymerization (ATRP) in THF solution using allyl 2-bromoisobutyrate as initiator and Cu(I)Br as catalyst. Under the adopted conditions the living centers concentration is found to be constant throughout the polymerization process and well defined chain end-groups are obtained. All the obtained polymeric samples, having average molecular mass ranging from 3300 to 14000g/mol, exhibit smectic and nematic liquid-crystalline phases on heating, with transition temperatures strongly dependent on polymerization degree, as characterized by differential scanning calorimetry and polarized optical microscopy. The photomechanical effects (i.e. the dependence of volume and density) exhibited upon trans-to-cis and cis-to-trans photoisomerization of the azobenzene mesogenic groups have been investigated by ellipsometry and related to molecular weight, with particular attention to important parameters for potential applications such as the relative variation of total volume, response time, stability and reproducibility. [Copyright &y& Elsevier]

This paper presents a summary of recent progress towards the development and upscaling of an emerging class of electrostatic power take-off (PTO) systems for wave energy converters (WECs), called dielectric elastomer generators (DEGs). DEGs are electromechanical devices able to convert mechanical energy into electrical energy by exploiting the deformation of rubber-like dielectric materials. The high power density (in the order of hundreds of Watts per kilogram), good efficiency and ease of assembling, combined with the low-cost of the employed materials (a few euros per kilogram) and their intrinsic resilient/reliable response to mechanical shocks make DEGs a very promising option for the deployment of a future generation of WECs. In the last decade, some specific concepts of WECs based on DEGs have been devised and a considerable interest in the topic has been aroused in the wave energy community. Among the candidate DEG topologies for wave energy harvesting, recent studies have suggested that a specific layout, namely the axial-symmetric inflating DEG diaphragm, could be a very promising candidate for future upscaling. This paper first describes the operating principle of DEG PTOs and the effect of electro-mechanical material parameters on their energetic performance. With reference to the above-mentioned inflating DEG diaphragm topology, an overview of concepts for integration on WECs is then provided, with a special focus on advanced concepts enabling the achievement of dynamical tuning with the incoming waves. A general lumped-parameter modelling approach for the design of DEG-based WECs is proposed. Experimental activity carried out to date, i.e. dry-run laboratory tests, wave-tank tests and preliminary sea trials is reviewed, with the aim of showing the progression in the device's scale and performance. Finally, economical and technological considerations are outlined, in order to point out challenges, future research opportunities and to draft a roadmap for future research and technological transfer. • Recent advances on polymeric power take-off systems for wave energy converters called dielectric elastomer generators (DEGs). • Identification of a DEG layout suitable for oscillating water column and pressure differential wave energy converters (WECs). • General modelling framework for coupled DEG-WEC systems. • Review of experimental testing of scaled prototypes. • Roadmap and techno-economic considerations on the future development of WECs based on DEGs. [ABSTRACT FROM AUTHOR]

This paper represents an expert view from Europe of future emerging technologies within the wind energy sector considering their potential, challenges, applications and technology readiness and how they might evolve in the coming years. These technologies were identified as originating primarily from the academic sector, some start-up companies and a few larger industrial entities. The following areas were considered: airborne wind energy, offshore floating concepts, smart rotors, wind-induced energy harvesting devices, blade tip-mounted rotors, unconventional power transmission systems, multi-rotor turbines, alternative support structures, modular high voltage direct current generators, innovative blade manufacturing techniques, diffuser-augmented turbines and small turbine technologies. The future role of advanced multiscale modelling and data availability is also considered. This expert review has highlighted that more research will be required to realise many of these emerging technologies. However, there is a need to identify synergies between fundamental and industrial research by correctly targeting public and private funding in these emerging technology areas as industrial development may outpace more fundamental research faster than anticipated. • A set of emerging technologies in the wind power sector was identified and studied. • For each technology, an analysis of the main advantages and challenges was made. • Potential for scaling each technology was identified. • Technology Readiness Levels and their development trends were assessed. [ABSTRACT FROM AUTHOR]